An AVO meter (Ampere, Volt, Ohm meter) or a multimeter can measure several different electrical quantities, usually a current, voltage, and resistance. There are two kinds of multimeter, namely analog and digital.

Both multimeter has a socket or a hole for the probe step on the test rod. Positive hole is marked with a + symbol is usually red, common hole (negative) is marked with a COM or symbol - usually black. Some multi meters have a positive second socket, which should be used to measure high voltages.

Both types of meter has a rotary knob to select where the quantity to be measured. This rotary knob is often also used to select a range of measurements. On an analog meter, you must connect the negative probe to the common measurement points more negative and the red probe to the measuring point is more positive. When you connect it backwards, the needle will swing downward zero. Remove immediately the two probes because it will cause damage to the meter.

Digital meters often have features otopolaritas. With this feature, the meter will show a minus sign on the left digit readout, when both probes are connected to the measurement points in reverse.

With an analog meter, there is a reading error problem when you do not read the measurement scales in a straight line from the top. Such errors are called parallax error. To help you avoid this, the meter is equipped with a curved mirror on the scale readings. You can see the reflection or shadow of the needle gauge on this mirror. When doing readings, move your head left and to right until you get the shadow coincides with a needle gauge needle. This ensures that you are looking straight down the scale and the reading will be correct.

Digital meters may also have features auto ranging. This feature allows the meter to choose the appropriate range automatically when the measurement was made.


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  1. Another informative blog… Thank you for sharing it… Best of luck for further endeavor too.

  2. In Russia this device is named "Tester".

  3. @ Electrical Contractor Houston, Nasty: Thanks for your comment and your input


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